Steam boiler of the flash type



Juiy 2, 1935.

H. BIDWELL STEAM BOILER OF THE FLASH TYPE Filed July '7, 1950 A TTORNEY.

Patented July 2, 1935 STEAM BOILER OF THE FLASH TYPE Howard Bidwell, Amherst, Mass., assignor of one-half to Linus H. Jones, Amherst, Mass.

Application July 7,V 1930, 'Serial No. 465,849

12 Claims. (Cl. 21S-38) This invention relates to improvements inthe upper and lower water surface is located on a method of maintaining amore consistent andunilevel Wit-h the upper and lower Water levels in the form Water level in steam boilers, and apparatus small boiler, as determined by the water rlevel of for heating and operated by electricity. the small boiler before and after the valve is 5 lobjectof the invention is to providey an apopened to an autoclave, or other steam receiving Y5 paratus for reducing the change in Water level receptacle. One of the purposes of this supplein steam boilers and quickly heating the same. mental boiler arrangement is to conserve the heat Heretoforazso far as I am aware, it has not been required to raise ,the water `in the small boiler .the practice to provide a steam generating unit to the required pressure and temperature, before i with a supplemental reservoir for building up the valve is opened. When the valve is opened 10 the. required vWater level and steam pressure. the Water in the supplemental boiler will auto- Broadly, my invention comprises an electric matically flow into the Vsmall main boiler to re `.boiler that is especially applicable to such process place the :gi'eiterpo'tmn of the water Withdrawn Work Where it is desirable to obtain steam presin the form of :steam and to thereby reduce the 1,5 Sureimmediately, when high pressure steam canchange in Water level in the small main boiler.

not be economically or conveniently furnished, Itis to be understoodthat mostof the steam which particularly, during the non-heating months. passes from the small main boiler intothe auto- The original installa-tions of this type of boiler clave is condensed and is then returned to the were in connection with sterilizers, for example, boiler andtllat :the portion 0f the Steam which a. necessary equipment of biological laboratories is lost .and does not so return is so small that it 20 and hospitals. However, the apparatus is of such will be only after Several 'Operations of the autodesign and flexibility that it can be adapted to a Clave thatritfwill 'be necessary t0 add Walter YOIn great variety `of uses, particularly, in the indus- Some :Source 0f Supply lt0 rplae that SO 10St- ,trial eld. Such data ,and descriptions recorded Such make-11D Water ELS may 'be inquired from in Athis paper were obtained from experiments tmGtOimBCa-n be Supplied by opening the valve 25 conducted by `applying steam from this, type 0f I5 :and permitting water to ynow from some outelectric boiler to a steam sterilizer. Side SoulCe through the pipo I4 into the boiler l.

The sterilization of media on which is culti- The' heating Unit inthe bOileI iS equipped With vated ,parasites of animals, man .and plants, is an independent circuitclosing device which opernot a rule of thumb procedure. The constitu- @tes at yConstant pressure and temperature, ad- 30 ents of the media, particularly sugars, `may break J'uStd OI a definite` DIeSSule. down if heat is .applied beyond .a certain period Blfi'flyjund 'SDCiiiCa'lly Stated, Iny iinDlOVeof time. It is very desirable to obtain a sterimntfCOInDiiSeS the -fOllOWing lizing :pressure (fifteen pounds) in the shortest First, a Small Cylindrically Shaped Steam boiler possible time and to maintain it n@ longer than of such shape and dimensions that the diameter between fifteen and twenty minutes. Frequently iS only sufficiently large in Order t0 allow, in a there is much material to be sterilized and the practical manner. the insertion of a standard or time "element in non-productive work on the .part other VWater immersion .electric heating element of the attendant and the sterilizer becomes a (the SiZB'OI lieatgenelating Capacity of the heat- 40 costly factor. It was just this combination of ing element, aS Well aS Vthe boiler, being detelli0 conditions, plus the lack of direct high pressure mined fby the steaming TequirefnentS that are, steam that prompted the construction ofthe elecplaced On the boiler), and, t0 be 0f Only Suftric boiler. A supplemental boiler is provided for iCieIlt length OI height aS to allOW, With leaSonreducing the .change in Water level in the small able Steam Space, Only SuiiCient Water Capacity boiler. The capacity of this boiler is very nearly between allowable high Water level and allowable equal tothe volume of water that is converted lOW Water level; Such VOlunle 0f Water as that intosteam, when the valve is Aopened inthe stem required With TeaSOnable niaigin for Safety to pipe which connects 'the small steam boiler, .on ll 'the autoclave, oven, or other pressure vessel an autoclave for example. The water supplied used in 'conjunction 'With Steam 0f the required by the small boiler is .therefore a minimum and pressure or temperature for steriIiZing, or other 5U the changein water level is reduced. Thesuppleindustrial purposes. mental fboiler'isprovided with a pipe connection, Second, employing electric control, automatic both aboveand below the water lines of the small or manual, whereby 'a 'higher pressure may Vbe boiler. 'This supplemental boiler is so located carried, maintained or built up inthe boiler than is? with reference .to the small main boiler that its that at which the autoclave, `or `other apparatus in question, is being normally operated, in order that when the autoclave is closed, and with the charge therein to be sterilized and ready for the admission of steam, the required pressure and temperature on the autoclave or vessel may be available in the minimum space of time, due to the heat energy contained in the water in the small boiler under a higher pressure and temperature than that required in the autoclave and with such pressures and manipulation that when the pressure of the boiler and autoclave are equalized, the pressure required on the autoclave or vessel is available, without delay.

The principle underlying the eiciency of this apparatus may be brieflly stated as follows:

The electric boiler is of small water capacity, but is constructed to carry a high steam pressure. When the charge has been placed in the sterilizer and all is in readiness for the admission of steam, therrequired pressure and temperature on the sterilizer may be available in a minimum space of time, due to the heat energy contained in the water in the small boiler under a higher pressure than'that required in the sterilizer and with such pressure and manipulation that when the pressure of the boiler and sterilizer are equalized, the pressure required o-n the sterilizer is available without delay. An automatic pressure control switch will maintain the required sterilizing pressure for whatever period is necessary.

When successivev charges vare to be sterilized, the second charge goesinto the autoclave while the whole system is hot.' During theV interval of cooling down the first charge so that it can be removed, another high pressure of 90 pounds is being built up from the 15 pounds inthe electric boiler. The gures have been obtained which showed that it took eight minutes with an energy consumption of 1.1 kilowatt-hours. During this intervalV of eight minutes, the iirst charge was removed and a new charge of twelve liters in twoliter flasks was placed within thesterilizer. The temperature of this water was'54" F. Thetotal energy consumption from the time the electric boiler was shut off from the first charge to the time a sterilizing pressure was Obtained on the second charge was 1.6 kilowatt-hours.v This energy was consumed -in building up a pressure from 15 to 9() pounds, in clearing the sterilizer of air, and raising thepressure'within the-sterilizer from to 15 pounds. Y K Y From these figures, one can easily estimate the cost Vof energy used in accomplishing this-type of work. Other advantages, not discussed here, include the great rapidity in obtaining required Y pressures, the ease of maintaining a reserve `supply of steam that can be quickly applied and a greater eiciency of labor on the part of the attendant. The installation from which the above data was obtained hasv increased they work done by this sterilizer byv per centj andv moreover has given an ease and speed of manipulation that has far exceeded expectations. In addismall amounts of steam for short intervals of time'.

Referring to the drawing:

Fig. 1 illustrates the steam boiler with the smallrauxiliary water boiler and electrical connections to the source of electrical energy, and

Fig. 2 is a sectional view of Fig. lV through the axis of the boiler, an enlarged sectional detail View of the small boiler showing the electric heating unit therein and the small supplemental boiler which is connected to the small main boiler.

Referring to the drawing in detail:

I designates the small steam boiler having the lagging covering 2, as shown in Fig. 2 with the electric heating coils or unit 3 therein which closely ts the interior diameter of the boiler. This unit is secured in place by means of the threaded openings d in its lower end, as shown. 5 indicates a steam pipe which is connected to the upper end of the small boiler VI by means of the threaded opening e, and l Vis a shut-off valve in the pipe 5. The other, or upper end of the steam pipe is understood as being connected to and has communication with an autoclave, or other steamreceiving receptacle, as shown in dotted lines at 8. 9 designates the small auxiliary water supply boiler or auxiliary water chamber, It a pipe connecting the bottom of the auxiliary boiler with the bottom of the mainboiler, at II. I2 is a draw-oi pipe having the valve I3. It is a main water supply pipe having a shut-oli I5 therein. I6 is a pipe connected to the upper side of thevsmall water boiler 9. Ii is a steam pressure gage connected to the pipe I8. I9 designates an electric thermostat which is electrically connected to the switch 28 in the main circuit wires 2i, which supplies current to the heating units 3. 22 is a baille plate.

The high water level is indicated at 23, which is the same level as that in the small boiler E at 24. The low water level is indicatedat 25 and thecorresponding low water level at 26.1

21 is a transformer, 23 the main power lines having a switch 29 therein. 39 is an electromagnetic switch in the circuit wires 3| and 32 to the thermostat I9. 33 andY Se are the wires connected to the'primary windings of the transformer 27. 35 are the circuit wires of the three phase system connected to the heating units 3. 36 are the supporting legs. The short pipe 3l connects the small auxiliar water boiler 9 to the main boiler I.

When the apparatus is started, the water level is at the lines 23 andr2l, and the boiler I is completely filled, as shown. As heat is applied to the boiler I, heat is transmitted to the water in the boiler!! bythe pipe 3l. When the valve 'Il is opened and some oi' the water in the! boiler I- at high temperature and pressure, as 60 lbs. is lconverted into steam, water will then ilow from boiler 9 into boiler I through the pipe I9. This will operate to restore the water level in 'the boiler I. In other words, the water fromV boiler 9 serves to reduce the change in water level in the boiler I, when the valve 'I is ,opened for sterilization, or other commerciall purposes, as cleaning or steaming garments. Y

The operation may be described as follows: itV

ture and pressure for. sterilization, or other purposes, when the valve 1 in the pipe `5 .isfopened yIn other words, the specific volume of steam at a denite pressure and temperature in the receptacle 8 is .determined by the quantity of water in the small boiler I, when it is ata definite pressure and temperature, before the valve l is opened, wherebythe vsmall volume `oi water, or some .of it in the boiler I is Vimmediately converted into steam, when `this valve is opened in order to .produce 'the required temperature and pressure in the receptacle .8 -for sterilization, or other purposes.

Assume `that the water in the small boiler at :starting is at .the Vhigh water line level, indicated at .2.3. The main switch 29 and the electromagnetic switch v2l) are closed yand an electric current is flowing to the heating'units .3 by means of .the wires 2l and 35. The steam `generated will yrise in pressure until the gage I l indicates, say 60 lbs., at which pressure the pressure control con-v tacts I!! would open, if set for this pressure. The Ymanual switch 29 is understood as being closed. As soon as the contact at I9 opens, a current ceases to flow through Vthe coil 30, which opens the electromagnetic switch 20 and cuts of the current to the heating units 3. The current in this circuit operates the part 301 and opens the circuit in the wires 35 to the heating unit. The operator now opens the valve 'I and allows steam at 60 pounds to enter the receptacle 8. By reason of a sudden release of the pressure, a sufficient quantity of water in the boiler I is converted into steam and passes into the receptacle at 15 lbs., or the desired sterilizing pressure, which is the usual sterilizing pressure. The low water level is now indicated at 25, when the water in the boiler 9 would be about one-half used.

In order to indicate the sterilizing temperature at 15 lbs. pressure, the steam gage I1 is employed. The low pressure control contact I9 will open at 15 lbs., or at the desired pressure. When the pressure reaches 15 lbs. pressure, the coil 30 again operates to open the electromagnetic switch.

It will be seen that the boiler I serves to maintain the water level nearly constant at all times, and also the steam space.

What I claim is: i

l. In combination with a steam receiving receptacle, as an autoclave, a steam boiler of small capacity, means for heating the same, means for automatically supplying water to the small steam boiler when steam is admitted into the autoclave whereby the change in the water level in the small steam boiler is reduced, said means comprising a supplementary boiler having its upper, inner surface located in substantially the same horizontal plane as the high water level of the small steam boiler and having its lower inner surface located in substantially the same horizontal plane as the low water level of the small steam boiler, the supplementary boiler having pipe connections to the small steam boiler both above and below the water level in the small steam boiler, and a pipe connection from the small steam boiler to the supplementary boiler midway between the high and low water levels in the small Steam boiler.

2. In a main steam boiler, of small water and steam capacity, a supplemental boiler, means for connecting the supplemental boiler to the main boiler, comprising pipe connections at its upper, lower and intermediate points, the water capacity of the supplemental boiler being in addition to and supplementing the amount of water available from the main boiler between high and low water levels of .the main boiler, .and means for heating the water in the main steam boiler comprising electric units which .substantially fill the .same up to vthe low water level.

3. In combination, a 'boiler .adapted to raise the temperature of an .autoclave or other receptacle to its operating temperature within a short period of time, said .boiler being adapted to be filled with water when the Yautoclave is not in operation, means for heating the water in said boiler to a temperature and corresponding pressure in excess of that required in the autoclave, means for permitting steam to fiow from the boiler into the autoclave to heat said auto- .clave whereby the pressure and temperature in the .boiler is reduced thereby utilizing the latent heat of vaporization ofthe water and a portion of .the water passes from the vboiler into the autoclave in the form of steam, an auxiliary Water chamber, connections between said boiler and sai-d water chamber providing water :circulation therebetween while heating and also providing means for the water to flow from the latter into the former to reduce the change in level of the water in the boiler due to the withdrawal of the portion of said water which passes into the autoclave.

4. In combination with a steam boiler of small steam capacity, an auxiliary water chamber, and permanent connections at two different levels each of which is below the high water level between said chamber and said boiler to provide water circulation therebetween so that the temperature of the water in said chamber will be substantially as high as that of the water in said boiler.

5. In combination with a steam boiler of small steam capacity, an auxiliary water chamber, connections between the top of said chamber and the boiler at a portion thereof above the high water level, a second set of connections between the bottom of said chamber and said boiler at a portion thereof below the 10W water level, and a third set of connections between said chamber and said boiler substantially midway between the high and low water levels.

6. In combination, a steam boiler having vertical dimensions substantially greater than any of its horizontal dimensions, an auxiliary water chamber having a horizontal dimension substantially greater than any of its vertical dimensions positioned adjacent to said boiler and at the water level thereof, and connections at two different levels each of which is below the high water level between said chamber and said boiler to provide circulation of water therebetween.

7. In combination, a steam boiler of cylindrical form with its axis positioned vertically, an auxiliary reservoir of cylindrical form with its axis positioned horizontally, said reservoir being positioned adjacent to the boiler at the water line thereof, and connections at two diiTerent levels each of which is below the high water level between said reservoir and said boiler to provide circulation of water therebetween.

8. Apparatus for supplying steam to an autoclave comprising a lower portion of small size for the reception of electric heating elements and adapted to be lled with water at both high and low water levels, and an upper portion having a horizontal cross-sectional area much larger than said lower portion whereby the change in water level caused by supplying steam to the autoclave is less than with apparatus having the same horizontal cross-sectional area at all levels.

9. In combination with a steam boiler `of small steam capacity, an auxiliary water chamber, and

connections at two different levels each of which is below the high water levelv between said boiler and said chamber to provide water circulation therebetween whereby the water in said chamber steam capacity, an auxiliary water chamber positioned at'the water level or said boiler, and connections to providefwater circulation therebetween comprising a passage from said chamber below the high water level and above its lower yportion directly to said boiler and another passage from the lower portion of said chamber to .the lower portion of said boiler positioned so as not to be directly heated by the boiler. v f 11. In combination, a steam boiler having a uniformY horizontal cross-sectional area throughiaoo'zosll chamber'connected with said boiler and sopositioned that its entire water capacity is available before the level, of the water is reduced to the top of said heating element. v

12. A steam Aboileradapted to furnish a predetermined quantityfof steam Ywith a minimum change in water level and to provide water submergence for electrical heating elementssat all times comprising a compartment for heating elements having a small horizontal 4cross-*sectional area compared with its vertical dimension and a second compartment positioned at a level above the level of the top of said heating elementshavingV a large horizontal cross-sectional area compared with the iirst-named compartment and a small vertical dimension compared with the rstnamed compartment and a Aplurality of connections between said compartments to provideriree circulationY of water therebetween at temperatures below that necessary to generate steam.

HOWARD BIIDWELL. 

